galnetfandomcom-20200216-history
Human brain
The human brain is the main organ of the human 1 nervous system. It is located in the head, protected by the skull . It has the same general structure as the brains of other mammals , but with a more developed cerebral cortex . Large animals such as whales and elephants have larger brains in absolute terms, but when measured using a measure of relative brain size, which compensates for body size, the quotient for the human brain is almost twice as large as that of a bottlenose dolphin , and three times as large as that of a chimpanzee .2 Much of the size of the human brain comes from the cerebral cortex, especially the frontal lobes, which are associated with executive functions such as self-control, planning, reasoning, and abstract thought. The area of the cerebral cortex devoted to vision, the visual cortex, is also greatly enlarged in humans compared to other animals. The human cerebral cortex is a thick layer of neural tissue that covers most of the brain. This layer is folded in a way that increases the amount of surface that can fit into the volume available. The pattern of folds is similar across individuals, although there are many small variations. The cortex is divided into four lobes – the frontal lobe , parietal lobe , temporal lobe , and occipital lobe . (Some classification systems also include a limbic lobe and treat the insular cortex as a lobe.) Within each lobe are numerous cortical areas, each associated with a particular function, including vision, motor control, and language. The left and right sides of the cortex are broadly similar in shape, and most cortical areas are replicated on both sides. Some areas, though, show strong lateralization, particularly areas that are involved in language. In most people, the left hemisphere is dominant for language, with the right hemisphere playing only a minor role. There are other functions, such as visual-spatial ability, for which the right hemisphere is usually dominant. Despite being protected by the thick bones of the skull, suspended in cerebrospinal fluid , and isolated from the bloodstream by the blood–brain barrier, the human brain is susceptible to damage and disease. The most common forms of physical damage are closed head injuries such as a blow to the head, a stroke, or poisoning by a variety of chemicals which can act as neurotoxins , such as ethanol alcohol . Infection of the brain, though serious, is rare because of the biological barriers which protect it. The human brain used to be susceptible to degenerative disorders, such as Parkinson's disease , and Alzheimer's disease , (mostly as the result of aging) and multiple sclerosis .3 A number of psychiatric conditions, such as schizophrenia and clinical depression, are associated with brain dysfunctions, the nature of these is now well understood.4 The brain can also be the site of brain tumors and these can be benign or malignant. Psionics are also an important field but iare not limited to human brains and generally psionic abilities and the related diseases and injuries are addressed by Psionology , a sub dicipline of Neurology . 1 In this context all forms of Homo Sapiens of the species Homo Galactus 2 Homo Sares is a human species but is 1.5 % bigger. Brainers have three times bigger brains 3 These and many other brain diseases are very rare and easily treatable if diagnosed. 4 While United Earth medicine made great advances in medicine. The Saresii becoming Union members catapulted Neurology to new heights. Category:Medical Science Category:Exobiology